As a general practice for communication with high reliability, the reception side sends back to the transmission side a message for notifying ACK (ACKnowledgment) to indicate that a packet signal has been received normally, or NACK (Negative-ACK) to indicate that a packet signal could not be received normally, whereas the transmission side makes an Automatic Repeat reQuest (hereinafter, referred to as ARQ) where retransmission is repeated until the reception side receives it correctly, or the number of times of transmission reaches a predetermined number.
Another HARQ is also used where the interleave pattern or the puncture pattern is updated when the packet signal is retransmitted so that the reception side performs processes by using the signal that could not be received correctly at the previous time and the retransmitted signal, and thus, the reception performance is improved though the cost for mounting the device increases.